Why Some Meals Spike You and Others Don't

Two meals containing the same amount of rice can produce very different readings, because the carbohydrate is only one of the things that decides the size of a spike.

What changes the size of a spike

• The form the food is in. Indian glycaemic index testing found the same grain behaving very differently depending on preparation — jowar measured 84.1 as a roti and 61.3 as an idli. The study's authors concluded that being a whole grain does not by itself make a food low GI.
• What is eaten alongside. Protein, fat and fibre all slow the arrival of glucose. Rice with dal and sabzi is a different meal from rice alone.
• The order you eat in. Vegetables and protein first, grain last.
• How much. Portion is the largest single lever, and the easiest to misjudge.
• What you do afterwards. A ten-minute walk immediately after eating measurably lowers the peak that follows.

Test it rather than guess it. Take a reading two hours after a meal you suspect, note what was in it, and repeat for the meals you eat often. Within two weeks you will know your own three or four problem meals — which is far more useful than a general list of foods to avoid.

This is a different question from why the *same* meal reads differently on different days — that one is here.